The present invention generally relates to the field of radio frequency (RF) waveguides, and more particularly to a waveguide in which is mounted a finline and a photovoltaic switch for modulating the impedance of the waveguide.
In the past, modulation of insertion losses of waveguides has been achieved by transitioning from a finline to microstrip using PiN diodes, followed by a transition back to finline. This configuration requires a DC bias to the PiN diodes. However, this approach has a limited bandwidth and is relatively difficult to manufacture. Therefore, a need exists for a way to modulate the insertion loss of a waveguide structure that does not require multiple transitions and the need for applying a DC bias to a transition element.